Ariadne Oliver is Dame Agatha's alter ego, and Dame Agatha had tons of fun with her:

‘I enjoyed your last, Mrs Oliver,’ said Superintendent Battle kindly. ‘The one where all the Chief Constables were shot simultaneously. You just slipped up once or twice on official details. I know you’re keen on accuracy, so I wondered if—’

Mrs Oliver interrupted him.

‘As a matter of fact I don’t care two pins about accuracy. Who is accurate? Nobody nowadays. If a reporter writes that a beautiful girl of twenty-two dies by turning on the gas after looking out over the sea and kissing her favourite labrador, Bob, goodbye, does anybody make a fuss because the girl was twenty-six, the room faced inland, and the dog was a Sealyham terrier called Bonnie? If a journalist can do that sort of thing, I don’t see that it matters if I mix up police ranks and say a revolver when I mean an automatic, and a dictograph when I mean a phonograph, and use a poison that just allows you to gasp one dying sentence and no more.

What really matters is plenty of bodies! If the thing’s getting a little dull, some more blood cheers it up. Somebody is going to tell something—and then they’re killed first. That always goes down well. It comes in all my books—camouflaged different ways, of course.